Cunliffe 2005.

Study characteristics
Methods	Aim of study: to compare the efficacy and safety of a 1% clindamycin/zinc gel when applied to the face once daily or twice daily with a 1% clindamycin lotion applied twice daily for 16 weeks in participants with mild to moderate AV Design: parallel Unit of allocation: individuals Allocation: unclear Blinding: observer‐blind Duration of trial (from recruitment to last follow‐up): the study ran through autumn, winter and early spring Dropouts: 10/83 for clindamycin/zinc gel qd; 7/80 for clindamycin/zinc gel bid; 6/83 for clindamycin lotion bid
Participants	Population description: mild to moderate acne Setting: 8 centres in the UK, 1 in France and 1 in Germany Randomised number: 163 Age: 12 to 40 years Sex: either sex Severity of illness: mild to moderate acne graded between 2 and 7 with at least 15 inflammatory and 10 non‐inflammatory lesions, but fewer than 75 lesions of either type
Interventions	Name of treatment group: clindamycin/zinc gel n = 80 Description: a topical acne treatment in which CDP equivalent to 1% clindamycin ('clindamycin/zinc gel') presented in a gel formulation has received marketing authorisations in a number of EU and non‐EU countries Treatment period: 16 weeks Timing: twice daily Name of treatment group: clindamycin lotion bid n = 83 Description: 1% clindamycin lotion Treatment period: 16 weeks Timing: twice daily
Outcomes	Primary outcomes Participants' global self‐assessment of acne improvement (e.g. measured by a 4‐point scale: excellent, good, fair, and poor). Visual analogue scale, week 16 Withdrawal for any reason. 23 withdrawals during 16 weeks' study Secondary outcomes Change in lesion counts (total or inflamed and non‐inflamed separately). From baseline to week 16, but no usable data, P value reported Physicians' global evaluation of acne improvement. Visual analogue scale, week 16 Minor adverse events (assessed as total number of participants who experienced at least 1 minor adverse event). A 10‐point scale from zero (0) to severe (7–9) used but no usable data; reported number of minor adverse events Quality of life. Authors did not report this outcome
Notes	Funding: this study was sponsored by Strakan Pharmaceuticals Ltd. For interventions: authors also used a 'clindamycin/zinc gel qd [three times/day]' group, in which timing was different from control group (twice/day). Therefore, reviewers did not consider it in the analysis. Regarding outcomes: all primary and secondary efficacy variables at 16 weeks had conclusions based upon an analysis of the last observation carried forward (LOCF) for the ITT population only
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Although 'randomised' was mentioned, no details were reported for random sequence generation
Allocation concealment (selection bias)	Unclear risk	We judged an unclear risk of bias because the authors did not report this issue.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "An observer‐blind design was used due to the difficulty in blinding the two different topical formulations". Comment: blinding probably insufficient
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Quote: "The investigator and assessors of all clinical variables were blinded to treatment allocation to avoid bias" Comment: insufficient information about blinding method
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Twenty‐three (9%) patients failed to complete the study, withdrawal rates were similar across the treatment groups..." "All primary and secondary efficacy variables at 16 weeks had conclusions based upon an analysis of the last observation carried forward (LOCF) for the intention‐to‐treat (ITT) population". Comment: ITT analysis. similar withdrawal rates across treatment groups, and missing data sufficiently addressed
Selective reporting (reporting bias)	Low risk	Results reported for all prespecified outcomes in the methods section
Other bias	Low risk	No other potential bias identified